Selective Extraction of Zinc from Refractory Hemimorphite Using Iminodiacetic Acid as a Complexing Agent

An environmentally friendly process for the selective extraction of zinc from refractory hemimorphite using iminodiacetic acid (H(2)Ida) as a complexing agent was investigated. Thermodynamic simulations demonstrated that the partially dissociated protons and amino carboxylate anions synergistically affect the dissolution of hemimorphite. The experimental results were consistent with the theoretical analyses. Under optimal conditions, the leaching extraction of zinc was above 88% and that of iron was below 4%. Furthermore, the complexing agent could be recovered from the leaching solution at the isoelectric point by adding dilute sulfuric acid.